And BCAAS are usually more expensive.

Since i can't find any leucine powder atmym local nutrition stores, I have been using a BCAA with l-Valine, isoleucine and l-leucine.  Is there any drawbacks to this vs. regular leucine powder

Just make sure your getting at least 3g of leucine, i suggest Modern BCAA because they have a 8:1:1 ratio. Leucine being the highest, its got over 3g per serving.

Mmm, well, depends what you believe I guess. I have read that the metabolism of leucine requires the other two amino acids in a 2:1:1 ratio, and leucine alone can actually deplete the blood levels of the other 2 BCAAs, which over time could actually short circuit protein synthesis because you’ll have a lack of substrate. A balanced BCAA blend may be superior because you are providing it in a 2:1:1 ratio which is going to prevent that depletion of isoleucine and valine. Additionally, studies in humans that have shown beneficial body composition effects of BCAA supplementation using a 2:1:1 ratio. This 2:1:1 ratio is supported by research. This is a fact, not conjecture or an opinion, or based on anecdotal evidence. I don't know of any equivalent research that has proven leucine alone is superior... only Kiefer is saying so. As far as I'm aware, research of higher ratios (4:1:1, 8:1:1) etc. hasn't been done, so jury is out on this I guess.

Muscle tissue does need isoleucine and valine to metabolize leucine and stimulate m-TOR, however, if you're eating regularly, then there should be some of these amino acids from your last meal with which you can metabolize leucine ingested on its own.I think higher ratios are fine because we're in the business of eating animal tissue on CBL, which provides fair amounts of BCAAs, just not free form.However, the main reason Kiefer advises taking leucine is to spike insulin.  I have seen claims that isoleucine stimulated insulin release as well, but not valine, so pure leucine, and consequently a higher ratio BCAA blend, would be best for this purpose.If you're planning on taking leucine on it's own outside of a post workout shake, then BCAAs are better, but it likely won't matter too much either way.